A1 Journal article (refereed)
Droplet digital PCR as a tool for investigating dynamics of cryptic symbionts (2021)

Hiillos, A., Thonig, A., & Knott, K. E. (2021). Droplet digital PCR as a tool for investigating dynamics of cryptic symbionts. Ecology and Evolution, 11(23), 17381-17396. https://doi.org/10.1002/ece3.8372

JYU authors or editors

Hiillos, Anna-Lotta
Thonig, Anne
Knott, Emily

Publication details

All authors or editors: Hiillos, Anna‐Lotta; Thonig, Anne; Knott, Karelyn Emily

Journal or series: Ecology and Evolution

eISSN: 2045-7758

Publication year: 2021

Publication date: 22/11/2021

Volume: 11

Issue number: 23

Pages range: 17381-17396

Publisher: Wiley

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1002/ece3.8372

Research data link: https://datadryad.org/stash/dataset/doi:10.5061/dryad.jwstqjq90

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/78778

Abstract

Interactions among symbiotic organisms and their hosts are major drivers of ecological and evolutionary processes. Monitoring the infection patterns among natural populations and identifying factors affecting these interactions are critical for understanding symbiont–host relationships. However, many of these interactions remain understudied since the knowledge about the symbiont species is lacking, which hinders the development of appropriate tools. In this study, we developed a digital droplet PCR (ddPCR) assay based on apicomplexan COX1 gene to detect an undescribed agamococcidian symbiont. We show that the method gives precise and reproducible results and enables detecting cryptic symbionts in low target concentration. We further exemplify the assay's use to survey seasonally sampled natural host (Pygospio elegans) populations for symbiont infection dynamics. We found that symbiont prevalence differs spatially but does not show seasonal changes. Infection load differed between populations and was low in spring and significantly increased towards fall in all populations. We also found that the symbiont prevalence is affected by host length and population density. Larger hosts were more likely to be infected, and high host densities were found to have a lower probability of infection. The observed variations could be due to characteristics of both symbiont and host biology, especially the seasonal variation in encounter rates. Our findings show that the developed ddPCR assay is a robust tool for detecting undescribed symbionts that are otherwise difficult to quantify, enabling further insight into the impact cryptic symbionts have on their hosts.

Keywords: infections; populations; host species; host animals; parasites; symbiosis; ecosystems (ecology); evolutionary biology